The present invention relates to a rigidly lockable straight-action breech block for an externally driven automatic weapon of the type including a control roller having control grooves which are engaged in a form locking manner, by means for transporting the straight action breech block, in which a firing pin is displaceably mounted, so as to move the firing pin into its firing position, and locking device for the breech block which includes two camming elements which are arranged to move two locking bars, which are located on opposite sides of the straight-action breech block and linearly displaceable transversely to the path of movement of the breech block, in opposite directions.
A rigidly lockable straight-action breech block has already been described in Federal Republic of Germany Patent Application Serial Number P 32 04 722, corresponding to allowed U.S. patent application Ser. No. 06/468,169, now U.S. Pat. No. 4,807,513. However, this previously described arrangement requires two oppositely rotating control rollers to control and lock the straight-action breech block. To lock the breech block, a camming disc disposed on each control roller displaces two locking bars moving in opposite directions either toward one another into the locking position or away from one another for unlocking. This arrangement and mode of operation ensures a reliable lock but it can be used only for use with two control rollers. During the return movement of the firing pin, which is displaceably disposed in the breech block, from a firing position into a rest position, it is further considered to be a drawback that, in the rest position, the firing pin is held by a spring which is subject to wear so that, under certain circumstances the safety of the weapon may be adversely affected.